Applications

Tektronix
brings you the first available high-speed differential SMA input probe.
The P7350SMA provides a tool for measuring differential signals in
a 50 Ω signaling environment. Before the introduction of the P7350SMA,
most serial data compliance measurements required cabling a differential
signal to two oscilloscope channels and applying waveform math to
calculate the difference. By integrating a dual 50 Ω termination network
and a differential amplifier in the probe head, the P7350SMA measures
a differential signal pair on each channel of a multiple channel oscilloscope.
Since many of the new high-speed serial data standards define differential
signaling on multiple channels, the P7350SMA provides a more efficient
measurement solution.

The P7350SMA probe architecture includes
an input termination network, a differential buffer amplifier, and
a common mode DC bias port. Since many differential data signals operate
with a nonzero DC common mode voltage, the DC bias port allows for
more flexible interfacing to these logic families. For applications
requiring a common mode DC termination voltage, that voltage can be
supplied to the P7350SMA DC bias port through a standard banana plug
connector. For other differential measurement applications, such as
AC-coupled and some DC-coupled high-frequency 8B/10B encoded data
streams, the DC bias port can simply be left unconnected.

Input
signals use SMA connectors to attach to the input termination network,
implemented on a laser-trimmed hybrid circuit for signal fidelity
and high-frequency response. The linear buffer amplifier converts
the differential input signal to a single-ended output and drives
the output signal down the probe cable at full bandwidth.

An
active differential buffer amplifier in the probe head enables the
P7350SMA probe to move the measurement interface from the oscilloscope
front panel to the circuit-under-test. This can reduce the length
of electrical interconnect cabling, which for multi-gigabit data signals
also reduces frequency-dependent loss distortion in signal measurements.
The P7350SMA is connected to an oscilloscope with the patented TekConnect
Interface.